The invention concerns a procedure for testing an electrical network for data transmission.
In data-transmission and data-communication technology, a number of nodes are linked together through a network. As a node, a computer system as an example or a similar system may be available, and as a network, optical-fiber cables arranged in a star-like configuration may be provided, for example. With the help of existing transmission mechanisms, it is possible that data from one of the nodes can be transmitted through the network to any other arbitrary node.
This kind of transmission mechanism consists in making information available which, proceeding from a first node, indicates the path to a destination node. If data from the first node are to be transmitted to the destination nodes, then, based on this information, the first node can determine which is the next node to which it must send the data on the way to the destination node. This next node, using the information specified above, can determine in the same manner the next node on the path to the destination node and send the data correspondingly. This is repeated until the data reach the destination node and the transmission of the data is completed successfully.
It is possible that one of the nodes of the network has a defect, and that a transmission of information through this node is therefore impossible. This has the result that not only is the node which is impaired by the defect no longer accessible, but any other nodes which are arranged beyond the defective node on the path to an arbitrary destination node, and are hence "in the shadow" of the defective node, are also inaccessible. Typically, all of these nodes are viewed as inaccessible from the first node, therefore there is no differentiation between the nodes located "in the shadow" and which are thus not necessarily defective nodes, and the actual defective node.
It is conceivable that, in a large network, a defect in one single node has as a result that a large number of nodes lie "in the shadow." All of these nodes are regarded, as mentioned above, as inaccessible without differentiation as seen from the first node. Based on the large number of nodes reported alone it is hardly possible for a user to detect the actual defective node and then eliminate the defect.